why does standard configure uses -Os?

[Chris Jones]

> On 24 Dec 2017, at 7:57 pm, Ryan Schmidt <ryandesign at macports.org> wrote:
> 
> 
>> On Dec 24, 2017, at 04:36, Chris Jones wrote:
>> 
>> In general its not possible to say one setting will always perform better than another,  its very use case dependant. For instance if you really want maximum numerical performance then -O3 can give significant gains, as it turns on a number of optimisations that can really help, like auto vectorisation. But, you would not want that as the default as some use cases might not like it. Its fine to have a default, but i would suggest each port should use whatever upstream has decided is its best optimisation level.
> 
> Ports are free to override configure.optflags if desired.

That’s not the same as simply letting the underlying  package decide, via its configure script or similar. That’s the point at which upstream gets to say what they feel is best.

>